# Dev Tools > Fast, free developer utilities that run directly in the browser. Tool inputs are processed locally and are not uploaded by Dev Tools. ## Tools - [Base Converter](https://devtools.piyushdoorwar.com/base-converter/): Convert UTF-8 text and bytes between binary, hex, decimal and octal, or convert arbitrary-size integers between any base 2–36 with two's complement views, instantly in your browser. - [Bcrypt Hash Generator](https://devtools.piyushdoorwar.com/bcrypt-generator/): Hash passwords with bcrypt at a chosen cost and verify a password against any $2a$, $2b$, or $2y$ hash, entirely in your browser. - [Certificate Decoder](https://devtools.piyushdoorwar.com/certificate-decoder/): Decode PEM certificates, chains, CSRs, and public keys to see the issuer, SANs, expiry, key details, and fingerprints, entirely in your browser. - [Chmod Calculator](https://devtools.piyushdoorwar.com/chmod-calculator/): Build Unix file permissions from a checkbox grid and read the octal, symbolic, chmod command, and umask defaults at once. - [Color Converter](https://devtools.piyushdoorwar.com/color-converter/): Convert colours between HEX, RGB, HSL, and OKLCH and check any pair against the WCAG contrast thresholds, entirely in your browser. - [Cron Expression Generator](https://devtools.piyushdoorwar.com/cron-expression-generator/): Build, parse, and explain cron expressions in plain English, then preview the next scheduled run times in any time zone. - [Crypto Generator](https://devtools.piyushdoorwar.com/crypto-generator/): Generate cryptographically secure passwords and hashes, and analyse password strength against dictionary, l33t, keyboard, sequence, repeat and date patterns, locally in your browser. - [CSV ⇄ JSON Converter](https://devtools.piyushdoorwar.com/csv-json-converter/): Convert CSV to JSON and JSON back to CSV with delimiter auto-detection and type inference, and browse the data as a sortable table. - [Docker Run to Compose Converter](https://devtools.piyushdoorwar.com/docker-compose-converter/): Convert docker run commands into a docker-compose.yml with ports, volumes, environment, networks, healthchecks, and limits mapped, locally in your browser. - [Encoder / Decoder](https://devtools.piyushdoorwar.com/encoder-decoder/): Encode and decode text with Base64, Base64url, URL percent-encoding, and HTML entities, and turn files into Base64 or data: URIs and back, locally in your browser. - [.env ⇄ JSON ⇄ Shell Converter](https://devtools.piyushdoorwar.com/env-json-shell-converter/): Convert environment variables between .env files, JSON objects, and shell export lines for Bash, fish, and PowerShell, locally in your browser. - [Fake Data Generator](https://devtools.piyushdoorwar.com/fake-data-generator/): Design a schema and generate realistic JSON test records with names, addresses, IDs, dates, numbers, and nested fields. - [File Compressor](https://devtools.piyushdoorwar.com/file-compressor/): Compress files locally in your browser with multiple algorithms while comparing original and compressed sizes before download. - [Git Cheatsheet](https://devtools.piyushdoorwar.com/git-cheatsheet/): Find Git commands by task, grouped by category, with history-rewrite and data-loss badges, fill-in placeholders and one-click copy. - [Hash Generator](https://devtools.piyushdoorwar.com/hash-generator/): Compute MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes and HMACs of text or files, and check them against an expected checksum, entirely in your browser. - [HTML Preview](https://devtools.piyushdoorwar.com/html-preview/): Write HTML, CSS, and JavaScript in a live browser playground with an instant preview and downloadable output. - [HTTP Header Builder](https://devtools.piyushdoorwar.com/http-header-builder/): Build Basic, Bearer, or API-key auth headers live, decode existing ones, and copy curl, fetch, or HTTPie snippets. Everything stays in your browser. - [HTTP Status Codes](https://devtools.piyushdoorwar.com/http-status-codes/): Search every HTTP status code with plain-English meanings, when-to-use guidance, common mistakes, and the RFC that defines it. - [ID Generator](https://devtools.piyushdoorwar.com/id-generator/): Generate and inspect developer identifiers including UUID variants and ULIDs directly in your browser. - [Image Toolkit](https://devtools.piyushdoorwar.com/image-toolkit/): Convert PNG, JPEG, WebP, SVG, and BMP images locally, generate a full favicon and app-icon pack with its manifest, and optimize SVG markup — all in the browser. - [JSON Diff](https://devtools.piyushdoorwar.com/json-diff/): Compare two JSON documents with formatting, validation, and clear structural difference highlighting. - [JSON Formatter & Query](https://devtools.piyushdoorwar.com/json-formatter/): Format, minify, and sort JSON without reordering keys or rounding big numbers, then query it with JSONPath or jq, all in your browser. - [JSON ⇄ Toon Converter](https://devtools.piyushdoorwar.com/json-toon-converter/): Convert JSON to compact Toon format and Toon back to JSON locally, with validation, token savings, and copy-ready output. - [JSON ⇄ XML Converter](https://devtools.piyushdoorwar.com/json-to-xml-converter/): Convert JSON to XML and XML to JSON, or pretty-print, minify, and validate XML while keeping comments, CDATA, namespaces, and mixed-content spacing, locally in your browser. - [JSON ⇄ YAML ⇄ TOML Converter](https://devtools.piyushdoorwar.com/json-yaml-toml-converter/): Convert between JSON, YAML, and TOML in any direction, or format and validate each in place — Kubernetes manifests, CI configs, Cargo and pyproject files — locally in your browser. - [JWT Debugger](https://devtools.piyushdoorwar.com/jwt-debugger/): Decode, inspect, edit, and verify JSON Web Tokens with readable header, payload, signature, and timestamp details. - [Key Pair Generator](https://devtools.piyushdoorwar.com/key-pair-generator/): Generate RSA, ECDSA and Ed25519 key pairs in your browser with WebCrypto. Export PKCS#8/SPKI PEM, JWK with an RFC 7638 kid, and OpenSSH public keys with SHA256 fingerprints. - [Keyboard Event Inspector](https://devtools.piyushdoorwar.com/keyboard-event-inspector/): Inspect key, code, location and modifiers live as you type, and turn any press into a shortcut string and JS condition. - [Lorem Ipsum Generator](https://devtools.piyushdoorwar.com/lorem-ipsum-generator/): Generate lorem ipsum placeholder paragraphs, sentences, words, or list items locally and count them as you go. - [Markdown Editor](https://devtools.piyushdoorwar.com/markdown-editor/): Write Markdown with synchronized editing, safe live preview, local file opening, and export-friendly controls. - [Math / Expression Evaluator](https://devtools.piyushdoorwar.com/math-evaluator/): Evaluate expressions live with exact BigInt, degree/radian trig and clean float display, plus percentage calculators and a reusable session history. - [MIME Type Lookup](https://devtools.piyushdoorwar.com/mime-type-lookup/): Look up MIME types by extension, filename or Content-Type, with ranked results and copyable header, nginx and Apache lines. - [Open Graph / Meta Tag Generator](https://devtools.piyushdoorwar.com/meta-tag-generator/): Generate SEO, Open Graph and Twitter/X card tags with live, illustrative previews for Google, Facebook, X, LinkedIn and Slack. - [OTP Generator](https://devtools.piyushdoorwar.com/otp-generator/): Generate and verify TOTP and HOTP one-time codes (RFC 6238 / RFC 4226) with SHA-1, SHA-256 or SHA-512, import or build otpauth:// URIs, and scan the setup QR code. - [QR Generator](https://devtools.piyushdoorwar.com/qr-generator/): Create customizable QR codes for links, contact details, Wi-Fi, email, phone, UPI, and other common formats. - [Regex Cheat Sheet](https://devtools.piyushdoorwar.com/regex-cheatsheet/): A JavaScript regex reference with syntax, flags, lookaround, and a library of tested patterns for email, URL, UUID, and more. - [Regex Tester](https://devtools.piyushdoorwar.com/regex-tester/): Test regular expressions with live match highlighting, flags, capture details, navigation, and replacement templates. - [Slug Generator / String Escaper](https://devtools.piyushdoorwar.com/string-escaper/): Generate URL slugs and escape or unescape strings for JSON, SQL, shell, regex, and HTML attributes locally in your browser. - [SQL Formatter](https://devtools.piyushdoorwar.com/sql-formatter/): Format and beautify SQL queries locally with readable indentation and practical editor controls. - [Subnet Calculator](https://devtools.piyushdoorwar.com/subnet-calculator/): Calculate IPv4 and IPv6 subnets from CIDR notation: network, broadcast, netmask, usable host range, and address type, then split blocks and convert ranges to CIDR. - [SVG Placeholder Generator](https://devtools.piyushdoorwar.com/svg-placeholder-generator/): Create a sized, coloured placeholder image and copy it as SVG, a data URI, an tag or CSS, or download it as SVG or PNG. - [Text Case Converter](https://devtools.piyushdoorwar.com/text-case-converter/): Convert text into camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, and Title Case at once, with a line-by-line bulk mode. - [Text Cleaner](https://devtools.piyushdoorwar.com/text-cleaner/): Clean and convert lists locally: trim, sort, deduplicate, recase, add affixes, quote, join, transpose columns and truncate values. - [Text Diff](https://devtools.piyushdoorwar.com/text-diff/): Compare text side by side with added, removed, modified, and character-level differences clearly highlighted. - [Text Encrypt / Decrypt](https://devtools.piyushdoorwar.com/text-encryptor/): Encrypt and decrypt text with AES-256-GCM, using a password (PBKDF2-SHA-256, 600k iterations) or a raw 256-bit key, as a portable Base64 token, entirely in your browser. - [Timestamp Converter](https://devtools.piyushdoorwar.com/timestamp-converter/): Convert Unix timestamps to ISO 8601, human-readable and relative time across time zones, and back again, entirely in your browser. - [Unicode / Character Inspector](https://devtools.piyushdoorwar.com/unicode-inspector/): Find hidden and zero-width characters, inspect code points, Unicode names and bytes, and escape text for code. - [Unit Converter](https://devtools.piyushdoorwar.com/unit-converter/): Convert common measurements across length, area, volume, mass, temperature, time, speed, data, and more. - [URL Parser](https://devtools.piyushdoorwar.com/url-parser/): Break a URL into its scheme, host, port, path, query, and fragment, edit the query parameters in a table, and rebuild the URL without changing what you didn't touch. - [User-Agent Parser](https://devtools.piyushdoorwar.com/user-agent-parser/): Parse any User-Agent string into browser, engine, OS, device and CPU, flag bots and crawlers, and see this browser's Client Hints. Handles Edge, Opera, Samsung, iOS browsers, in-app browsers and frozen UA values. - [Word & Character Counter](https://devtools.piyushdoorwar.com/word-counter/): Count words, characters, sentences, paragraphs, and estimated LLM tokens, with reading time and word frequency. ## Additional resources - [Homepage](https://devtools.piyushdoorwar.com/): Browse and search the complete tool collection. - [Sitemap](https://devtools.piyushdoorwar.com/sitemap.xml): Canonical index of all public tool routes. - [Source code](https://github.com/piyushdoorwar/dev-tools): Project source and documentation.